A bit firm, having got implanted? (4)
I believe the answer is:
coin
'a bit' is the definition.
(old-fashioned term for a coin)
'firm having got implanted?' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'having got' says to put letters next to each other.
'implanted?' becomes 'in' (I can't explain this - if you can you should believe this answer much more).
'co'+'in'='COIN'
Can you help me to learn more?
(Other definitions for coin that I've seen before include "Invent a word or phrase - for money?" , "little money" , "Metal money disc" , "Invent (a new phrase)" , "Money; devise (a word)" .)